title: Do colonic bacteria contribute to cholesterol gall-stone formation? Effects of lactulose on bile.
abstract: Ten healthy middle-aged women volunteered for a study to test the effect of lactulose--a synthetic, non-absorbable disaccharide--on the colonic metabolism of bile acids and on bile lipid composition. Lactulose (60 g daily in eight cases, 39 g daily in two) was taken as a proprietary syrup for six weeks, and bile was collected by duodenal intubation before and immediately after six weeks. All subjects showed a fall in the percentage of the 7-alpha-dehydroxylated bile acid deoxycholic acid (mean 28.4 +/- SEM 3.7 to 15.6 +/- 2.4; p less than 0.002) and a rise in the percentage of the primary bile acid chenodeoxycholic acid (mean 33.2 +/- 42.9 +/- 2.9; p less than 0.001). The percentage of cholic acid rose in eight subjects but mean values did not differ significantly. Bile was initially super-saturated with cholesterol in most subjects and became less saturated with cholesterol in all but one (mean saturation index 1.40 +/- 0.11 to 1.19 +/- 0.07; p less these 0.005). These data support the theory colonic bacteria contribute to cholesterol gall-stone formation.
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001646:Bile / Q000187:drug effects* / Q000378:metabolism; D002635:Chenodeoxycholic Acid / Q000378:metabolism; D002769:Cholelithiasis / Q000209:etiology; D002784:Cholesterol / Q000378:metabolism; D002793:Cholic Acids / Q000378:metabolism; D003106:Colon / Q000382:microbiology; D003840:Deoxycholic Acid / Q000378:metabolism; D004187:Disaccharides / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007792:Lactulose / Q000494:pharmacology*; D008875:Middle Aged
chemical_list: D002793:Cholic Acids; D004187:Disaccharides; D003840:Deoxycholic Acid; D002635:Chenodeoxycholic Acid; D007792:Lactulose; D002784:Cholesterol